Aiming at beam collimation of laser diode,a method that can collimate the LD beam with single double-focus micro-lens is proposed based on the analysis of astigmatism. Theoretical analysis and ZEMAX simulation show that micro-lens with biconic surface can collimate fast and slow axes of the beam at the same time. The elliptical micro-lens with double-focus was manufactured by melting photoresist. Then the experiment of LD beam collimation was carried out,and the beam divergence angles before and after collimation were measured. The results show that double-focus micro-lens can collimate effectively.